Roof panel anti-flutter reinforcement

ABSTRACT

An anti-flutter structure, or reinforcement panel, for a roof panel supported on transversely extending roof bows. The reinforcement panel is attached to at least one of the roof bows with the flanges being disposed above the roof bow. The flanges extend longitudinally, and are resiliently compressed by the roof panel. The reinforcement panel has a body and flanges laterally flanking the body. The body is attached to one of the roof bows with the flanges being disposed above the roof bow. The anti-flutter material is disposed between the flanges and the roof panel.

TECHNICAL FIELD

This disclosure relates to roof panels supported on roof bows that aresecured together with an anti-flutter reinforcement that minimizes noiseand vibration.

BACKGROUND

In an effort to reduce overall vehicle weight, aluminum is proposed tobe used for both structural and exterior body panels. Aluminum roofpanels on large SUV vehicles are susceptible to thermal deflectionsduring the electro-coat and paint bake processes. Thinner gauge materialis preferred to be used on roof panels which increases the rate andmagnitude of thermal deflection compared to supporting roof bows thatare formed of thicker gauge material. The difference in thermaldeflection between the roof panel and supporting roof bows causes anincrease in the gap between these parts.

Anti-flutter material provided as a tape or mastic paste is applied tobows that support the roof panel during assembly prior toelectro-coating and the paint bake operations. The anti-flutter materialsupports the roof panel after curing where the roof panel is joined tothe roof bows. Anti-flutter material has a low modulus of elasticity anddoes not add strength or stiffness to the joint between the roof paneland the roof bows but instead expands to a limited extent to compensatefor the gap caused by differential between the thermal deflection of theroof panel and the roof bows. Generally, the gap between the roof paneland roof bows in the finished vehicle should be less than 6 millimetersto assure proper adhesion that, in turn, minimizes flutter of the roofpanel when the vehicle is driven.

This disclosure is directed to solving the above problems and otherproblems as summarized below.

SUMMARY

This disclosure is directed to a roof panel reinforcement thatcompensates for thermal deflection between roof panel and roof bows andthat is used as a carrier for an anti-flutter tape or other adhesivematerial. The roof panel reinforcement is comprised of a material ofappropriate grade and gauge that has a series of holes or slots definedby the reinforcement to enable the reinforcement to deflect upon contactduring the roof panel framing process. A nominal gap of approximately 3millimeters is established during the roof framing process that expandsduring the electro-coating and paint bake process. The flanges on thereinforcement spring back as thermal deflection occurs, to facilitateconforming the reinforcement to the roof panel. By the action of thereinforcement springing back to conform to the roof panel during thermaldeflection, it is possible to use an anti-flutter material havinglimited expansion characteristics.

According to one aspect of this disclosure, a roof assembly is disclosedthat comprises a roof panel, roof bows, a reinforcement panel, and ananti-flutter material. The roof bows extend transversely across andbelow the roof panel to support the roof panel. The reinforcement panelhas a body portion and flanges laterally flanking the body portion. Thebody is attached to one of the roof bows with the flanges being disposedabove the roof bow. The roof bows extend in the longitudinal directionand are resiliently compressed by the roof panel. The anti-fluttermaterial is disposed between the flanges and the roof panel.

According to another aspect of this disclosure, an anti-flutterstructure is disclosed for a roof panel supported on transverselyextending roof bows. The anti-flutter panel has a body and flangeslaterally flanking the body. The body is attached to at least one of theroof bows with the flanges being disposed above the roof bow. Theflanges extend longitudinally and are resiliently compressed by the roofpanel. The anti-flutter material is disposed between the flanges and theroof panel.

According to other aspects of the above this disclosure, thereinforcement panel may include upstanding walls between the flanges andthe body. The upstanding walls may be joined to the flanges at an uppercorner, and the upper corner may define a plurality of openings thatincrease the flexibility of the corner. The upstanding walls may bejoined to the body at a lower corner, and the lower corner may define aplurality of openings that increase the flexibility of the lower corner.

The roof bow may have outwardly extending flanges, and the reinforcementpanel may be attached to the outwardly extending flanges.

The flanges may exert a biasing force on the roof panel. The roof panelmay exhibit greater thermal expansion than the roof bows making the roofpanel move away from the roof bows when heated so that the flanges flexupwardly toward the roof panel.

The above aspects of this disclosure and other aspects will be describedbelow with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left/front perspective view of a vehicle showing a roof bowwith a reinforcement panel made according to one aspect of thisdisclosure.

FIG. 2 is a fragmentary perspective view of a vehicle showing areinforcement panel attached to the center of one of the roof bows.

FIG. 3 is a fragmentary top plan view of part of a roof bow attached tothe reinforcement shown in FIG. 1.

FIG. 4 is a fragmentary cross-section view of a roof panel, a roof bowflange and a reinforcement panel.

FIG. 5 is a fragmentary cross-section view of a roof panel, a roof bowflange and a reinforcement panel showing the roof panel being assembledto the reinforcement panel and the roof bow flange.

FIG. 6 is a fragmentary cross-section view of a roof panel, a roof bowflange and a reinforcement panel showing the roof panel assembled to thereinforcement panel and the roof bow flange.

FIG. 7 is a fragmentary perspective view of a vehicle showing analternative embodiment of this disclosure in which an integral combinedroof bow and reinforcement panel reinforcement panel is attached to thecenter of one of the roof bows.

DETAILED DESCRIPTION

The illustrated embodiments are disclosed with reference to thedrawings. However, it is to be understood that the disclosed embodimentsare intended to be merely examples that may be embodied in various andalternative forms. The figures are not necessarily to scale and somefeatures may be exaggerated or minimized to show details of particularcomponents. The specific structural and functional details disclosed arenot to be interpreted as limiting, but as a representative basis forteaching one skilled in the art how to practice the disclosed concepts.

Referring to FIG. 1, a vehicle 10 is illustrated that includes a roofassembly generally indicated by reference numeral 12. The roof assembly12 includes a roof panel 14. An intermediate roof bow 16 is shownsupporting the roof panel 14. As is well-known in the art, additionalroof bows and a windshield header are also used to support the roofpanel 14. A reinforcement panel 20 is assembled between the intermediateroof bow 16 and the roof panel 14. The reinforcement panel 20 could beassembled between the roof panel 14 and another roof bow or to more thanone roof bows as required to reduce flutter of the roof panel 14.

Referring to FIG. 2, a portion of a roof assembly 12 is illustrated thatincludes a pair of roof rails 22. A front flange 26 and a back flange 24are provided on the roof bow 16 that strengthen the roof bow.

Referring to FIGS. 2 and 3, the reinforcement panel 20 is attached tothe top of the roof bow 16 on the front flange 26 and the back flange24. The reinforcement 16 has a body portion 28, or body, and a rightflange 30 and left flange 32. A plurality of openings 36 are defined ateither or both of an upper corner 38 or lower corner 40 formed on thereinforcement panel 20. The openings 36 may be either circular holes,holes of other shapes, or slots. The upper corner 38 is located at thejuncture of one of the flanges 30, 32 and an upstanding wall 42. Thelower corner 40 is located at the juncture of the body 28 and theupstanding walls 42. A reinforcing rib 44 may be provided in the body toadd strength and rigidity to the body 28. The reinforcement panel 20 isfixedly attached by fasteners or welds to the front flange 26 and theback flange 24 of the roof bow 16.

Referring to FIG. 4, the roof panel 14 is shown above the reinforcementpanel 20 and the roof bow 16 with an arrow showing the direction thatthe roof panel is moved to be assembled over the reinforcement panel 20and the roof bow 16. The dashed lines in FIG. 4 illustrate the positionof the roof panel 14 as it contacts the anti-flutter tape 48.Anti-flutter tape is placed on the right flange 30 and left flange 32prior to assembling the roof panel 14. The anti-flutter tape 48 adheresto the lower surface of the roof panel 14 and the right flange 30 andleft flange 32 during vehicle assembly, electro-coating and paint bakeovens. The anti-flutter tape remains adhered to the roof panel 14 andright and left flanges 30, 32 when the vehicle is placed into service toprevent unwanted flutter noise and vibration.

Referring to FIGS. 5 and 6, compression of the flanges 30, 32 by theroof panel 14 during assembly is illustrated. A raised bead 50 of theroof panel 14 may be aligned with the reinforcement panel 20 to preventor minimize distortion of the roof panel in the area where thereinforcement panel 20 is attached to the lower surface of the roofpanel 14. Instead of anti-flutter tape, an anti-flutter mastic paste 52may be applied to the right flange 30 and left flange 32 prior toassembling the roof panel 14.

The spacing between the arrows on the left side of FIGS. 5 and 6 showthat the flanges 30, 32 are compressed by the weight of the roof panel14. For example, the initial spacing shown in the unassembled state inFIG. 5 may be 6 millimeters. In the after assembled state shown in FIG.6, the spacing may be reduced to about 3 millimeters. The upstandingwalls 42 extending above the body 28 of the reinforcing panel 20 allowthe flanges 30, 32 to flex toward the flange 24 of the roof bow 16 whileexerting a biasing force on the roof panel 14.

During subsequent processing of the vehicle, the roof panel is heated inthe electro-coating baths and in the paint ovens. The greater thermaldeflection of the larger and thinner roof panel 14 relative to thesmaller and thicker roof bow 16 causes the roof panel 14 to separatefrom the roof bow 16. When this occurs, the reinforcement panel 20reacts with the flanges 30, 32 springing back up toward theirpreassembled orientation.

Referring to FIG. 7, a combined roof bow and anti-flutter reinforcement60 is illustrated in a view similar to that of FIG. 2. Elements of theroof structure and reinforcement panel that are like those shown anddescribed with reference to FIGS. 1-6 are assigned the same referencenumerals for brevity. The combined roof bow and anti-flutterreinforcement 60 is attached to spaced roof rails 22 and includes a roofbow portion 62 and an anti-flutter reinforcement 64. L-shaped flanges 66are provided on the combined roof bow and anti-flutter reinforcement 60that are spaced above a body 68 by upstanding walls 70.

As previously described openings 36 are provided at an upper corner 38formed at the juncture of the L-shaped flanges 66 and the upstandingwalls 70. Lower corners 40 are provided at the juncture of the body 68and the upstanding walls 70. The openings are provided to increase theflexibility of the combined roof bow and anti-flutter reinforcement 60.A reinforcing rib 44 may be provided as needed to increase the strengthof the anti-flutter reinforcement 64.

The embodiments described above are specific examples that do notdescribe all possible forms of the disclosure. The features of theillustrated embodiments may be combined to form further embodiments ofthe disclosed concepts. The words used in the specification are words ofdescription rather than limitation. The scope of the following claims isbroader than the specifically disclosed embodiments and also includesmodifications of the illustrated embodiments.

What is claimed is:
 1. A roof assembly comprising: a roof panel; pluralroof bows extending transversely across and below the roof panelsupporting the roof panel; a reinforcement panel having a body andflanges laterally flanking the body, the body is attached to one of theroof bows, the flanges are disposed above the roof bow, extendlongitudinally, and are resiliently compressed by the roof panel; and ananti-flutter material is provided between the flanges and the roofpanel.
 2. The roof assembly of claim 1 wherein the reinforcement panelincludes a pair of upstanding walls between the flanges and the body. 3.The roof assembly of claim 2 wherein the upstanding walls are joined tothe flanges at an upper corner, and wherein the upper corner defines aplurality of openings that increase flexibility of the upper corner. 4.The roof assembly of claim 2 wherein the upstanding walls are joined tothe body at a lower corner, and wherein the lower corner defines aplurality of openings that increase flexibility of the lower corner. 5.The roof assembly of claim 1 wherein the roof bow has outwardlyextending flanges, and wherein the reinforcement panel is attached tothe outwardly extending flanges.
 6. The roof assembly of claim 1 whereinthe flanges exert a biasing force on the roof panel, wherein the roofpanel exhibits greater thermal expansion than the roof bows, and whereinthe roof panel moves away from the roof bows when heated and the flangesflex upwardly toward the roof panel.
 7. An anti-flutter structure for aroof panel supported on transversely extending roof bows comprising: areinforcement panel having a body and flanges laterally flanking thebody, the body is attached to at least one of the roof bows, the flangesare disposed above the roof bow, extend longitudinally, and areresiliently compressed by the roof panel; and an anti-flutter materialis provided between the flanges and the roof panel.
 8. The anti-flutterstructure of claim 7 wherein the reinforcement panel includes anupstanding wall between the flanges and the body.
 9. The anti-flutterstructure of claim 8 wherein the upstanding walls are joined to theflanges at an upper corner, and wherein the upper corner defines aplurality of openings that increase flexibility of the upper corner. 10.The anti-flutter structure of claim 8 wherein the upstanding walls arejoined to the body at a lower corner, and wherein the lower cornerdefines a plurality of openings that increase the flexibility of thelower corner.
 11. The anti-flutter structure of claim 7 wherein the roofbow has outwardly extending flanges, and wherein the reinforcement panelis attached to the outwardly extending flanges.
 12. The anti-flutterstructure of claim 7 wherein the flanges exert a biasing force on theroof panel, wherein the roof panel exhibits greater thermal expansionthan the roof bows, and wherein the roof panel moves away from the roofbows when heated and the flanges flex upwardly toward the roof panel.